Early Screening of Autism among 18 to 24 months Old Toddlers Using the Quantitative Checklist for Autism in Toddlers (Q-CHAT)

Objective The aim of the present study was to screen the toddlers who are suspected to be autistic in their well-child visits at age 18 to 24 months via the Quantitative-Checklist for Autism in Toddlers (Q-CHAT). Materials & Methods After the screening, the screen-positive cases were clinically assessed by a child psychiatrist and a child developmental psychologist. The total sample included 2467 toddlers; the mean total score of Q-CHAT was 30.64 (SD: 9.133). Result According to the clinical examinations, 6 cases met the criteria for autism (equal to 5.8% of screen-positive cases and 0.25% of the total sample), and 18 cases had a high probability of autism or other neurodevelopmental disorders. Conclusion This study showed that the toddlers who were at risk of autism could be screened in PHC. Also, Q-CHAT could be used as a screening tool in Iran.

Iran J Child Neurol. Autumn 2020 Vol. 14 No. 4 programs have been implemented in high-income countries, especially in the US (5). In recent years, some attempts have been made to establish early screening programs in health care systems of low-and middleincome countries (LMICs) (6)(7)(8).
Similar to many other LMICs, Iran is a novice country in the early screening of autism and other neurodevelopmental disorders. In recent years, some epidemiologic studies have focused on screening autism among Iranian children older than 2 years in different settings using different methods (9)(10)(11).
The literature has emphasized on detecting the children who are at risk of autism when they are 18 to 24 months old (2). It suggests that primary care is a good setting for early screening programs that can reduce the age at diagnosis (12). Accordingly, the present study aimed to design and investigate an early screening program in primary health care (PHC) system of Iran.

In the new edition of the Diagnostic and Statistical
Manual of Mental Disorders (DSM-5), the definition of autism has changed from a categorical disorder with different subgroups to a dimensional diagnostic category (1). Various screening and diagnostic tools have been developed to treat the symptoms of autism as a continuous concept rather than a category. (13). One of these tools is the Quantitative Checklist for Autism in Toddlers (Q-CHAT), which has recently gained attention as a level 1 screening tool for toddlers. It is a 25-item parent-report screening tool for autistic symptoms for toddlers aged 18-24 months. It measures developmentally relevant traits and behaviors associated with autism (14). The reliability and predictive validity of the Persian version of Q-CHAT have been investigated previously in a clinically referred samples of toddlers. The present study showed that the Persian version of Q-CHAT can distinguish toddlers who are at risk of autism from those who are typically developing (15). In the next step, this study aimed to investigate the feasibility of using Q-CHAT to screen toddlers who are suspected to be autistic at age 18 to 24 months in their well-child visits in the primary care setting of Iran.

Participants and Setting:
This population-based study aimed to investigate the feasibility of screening toddlers who are at risk

Data analysis
Data were analyzed using IBM SPSS Statistics version 23.0.

Results
In sum, a total of 2704 questionnaires were filled out, 138 of which were incomplete. In 99 questionnaires, the children were younger than 17 months, thus, the total sample size was reduced to 2467 toddlers. Based on the total Q-CHAT score, more than 35853 cases (29.8%) were screened positive and referred to PPRC. However, only 104 (12%) made an appointment. The mean age of those toddlers whose parents made an appointment for a psychiatric visit was 19.63 months (sd: 2.6), and 38.5% were female, and 61.5% were male. The mean of the total Q-CHAT score was 42.98 (sd: 7.27) and ranged from 35 to 72 ( Table 2).
The clinical evaluation, based on DSM-5 criteria and interviews with parents regarding toddlers' developmental and medical history, showed that 6 cases met the criteria for autism (equal to 5.8% of screen-positive cases and 0.25% of the total sample). Also, 18 cases were at high risk of autism or other neurodevelopmental disorders (equal to 17.3% of screen-positive cases and 0.73% of the total sample).
The mean of the total Q-CHAT score was 64.83 among autistic cases (sd: 9.21) and ranged 52 to 72. Also, this mean was 48.22 (sd:2.4) among high probability cases and ranged 44 to 53.

Discussion
This was the first study to screen autism before the age of 24 months in Iran using a screening tool (Q-CHAT), which considers the symptoms of autism as a continuous concept rather than a categorical one.
The mean of the total score of Q-CHAT among the participants was 30.64 (SD: 9.133). In another population-based study in Singapore, using-CHAT, the mean score of 18 months old toddlers was 35.57 (SD:7.21) and it was 33.2 among 24 months olds (SD:7.7) [13]. In a previous study in Iran, the mean of the total score for the typically developing group was 22.4 (SD = 6.26) on Q-CHAT and 50.94 (SD =12.35) for the ASD group [15]. In the In another study conducted in Mahabad, Iran, the prevalence of autism and ASD among 2 and 3 yearolds was reported as 15 per 10 000 and 77 per 10 000, respectively [9].

Limitations and Recommendations
The

In Conclusion
In sum, the present study revealed that the toddlers who were at risk of autism in PHC in Iran could be screened via Q-CHAT as a level 1 screening tool

Author Contributions
M.M has contributed to the conception and design of the study, analysis of data, and drafting the manuscript or figures.
Gh.Z has contributed to the conception and design of the study, analysis of data, and drafting the manuscript or figures.
H.Z has contributed to the conception and design of the study, analysis of data, and drafting the manuscript or figures.